As well-known, the magnetic disk apparatus is widely used as an external memory apparatus of a computer. As for a kind of the magnetic disk apparatus, a head-flying method and a head-contact method are used. In the head-flying method, the head is flown on a rotated magnetic disk to write and read information. In the head-contact method, the head is compulsorily contacted on the rotated magnetic disk to write and read information. In this case, a spacing between the head and the surface of the magnetic disk is reduced in comparison with the head-flying method. Therefore, in the head-contact method, recording density of the information greatly rises.
However, in the magnetic disk apparatus of the head-contact method, the head always contacts and slides on the surface of the magnetic disk. As a result, it is difficult to avoid the wear of the head and the disk. Therefore, in the head-contact method, in order to maintain the reliability, a method for reducing the wear is necessary. This is especially important where the contact area of the head is much smaller than the area of the magnetic disk surface. Therefore, the wear of the head is much larger than that of the disk. Accordingly, an effective means to reduce the wear of the head is desired.
In short, in the magnetic disk apparatus of the head-contact method, the problem of reducing the wear of the head remains.